Recently, with a progress of miniaturization and three-dimensionalization of semiconductor devices, it is required to improve processing accuracy of etching when processing the semiconductor devices. As one way to improve the processing accuracy of the etching, it is required to improve accuracy of a hard mask HM for dry etching which is formed on a substrate.
Conventionally, a hard mask is formed on a substrate through the following manner, for example. First, a film of a hard mask material such as SiN (silicon nitride) or TiN (titanium nitride) is formed on an entire surface of the substrate, and a resist layer having a preset pattern is formed on the hard mask material. Thereafter, the hard mask material which is not covered with the resist layer is removed by dry etching, so that a hard mask having the preset pattern is formed on the substrate. Subsequently, a part of the substrate which is not covered with the hard mask is removed by dry etching. Then, the hard mask is removed by a wet cleaning method or the like.    Patent Document 1: Japanese Patent Laid-open Publication No. 2009-249679
In the prior art, however, there are many various limitations on the hard mask material which covers the substrate. Such limitations include: (1) adhesivity between the hard mask and the substrate needs to be high (2) adhesivity between the hard mask and the resist layer needs to be high, (3) the hard mask material needs to be difficult to damage by heat treatment when forming the pattern on the resist layer, (4) the resist layer needs to be difficult to remove when the hard mask is etched, (5) the hard mask needs to be difficult to remove when the substrate is dry-etched, and (6) the hard mask needs to be easy to remove after the substrate is dry-etched. For these limitations, only a limited material such as the aforementioned SiN (silicon nitride) or TiN (titanium nitride) has been used as the hard mask material.